Solidpack vs aircooled chimney

[builderbob]

Read the industry guide to planning for a woodburner to help insure good draft. Very good article which Craig posted in another thread..

(broken link removed)

It goes through 6 factors a homeowner wanting a woodburner unit should consider and plan for. The more of the 6 factors a homeowner can get the "right" way, the less chance of having drafting problems, and smoke puffback into the room.

One of the factors is having the flue inside the heated envelope of the house, as opposed to in an outside (especially uninsulated) cold chase. This factor has directly influenced the design of our proposed house plans for the home we want to build.

But their discussion on this point does not directly come out and talk about solidpack vs aircooled chimneys.

I may be wrong, but it seems like this chimney choice directly relates to the "warmth" of the flue. Solidpack will keep the flue warmer all the way up than aircooled, and hence *should* draw better.

Is my thinking wrong on this issue? This aircooled vs solidpack is one big drawback to the Fireplace Xtrordinair unit in my book (since it is only approved for aircooled).

builderbob

 

[littlesmokey]

Flue is determined by the stove you install. You shouldn't be working from the "best" chimney back to the stove. A chimney way inside the envelope of the house is better because the flue gasses are not subjected to unusually low environmental temperatures. If you are building, you have the best choices, but start with the stove, fireplace, heater, insert, freestander.

The thinking to me is analogous to deciding the wall outlet design for your 220 service in a shop, and then buying only equipment that comes with the cord that matches the outlet. I prefer Hubbell twist lock 30 amp connectors, so I change the ends on the machines, not the machines that match the plugs.

Hope that makes sense, but the appliance should drive the accessories.

Take a deep breathe, and pick your unit..... Or do a generic service, best for as many units as possible and don't look back.

 

[builderbob]

Flue is determined by the stove you install. You shouldn't be working from the "best" chimney back to the stove.. .......

Some might disagree with that. Some would say the "chimney system IS the most important part of any installation".

So, if I start with the chimney I would like to have---solidpack---and there happen to be some quite acceptable fireplaces that are approved with solidpack, I end up in a very good position.

I think one criteria for judging a stove/zc fireplace against others should be "what type of chimney is the unit approved with". If it is approved with both solidpack or aircooled---10 points.
If it is approved solidpack only ---8 points.
If it is approved aircooled only---3 points.

But that is just my opinion based on a predilection for solidpack over aircooled chimney.

Builderbob

 

[Highbeam]

I agree. Solidpack is better. I don't want to have to worry about air channels being plugged with spiders and therefor eliminating the air cooling and then catching my house on fire. I don't want air movement outside of the chimney since the energy moving air up the air gap is being sucked from the heat of the flue gas and that must be cooling the flue gas somewhat.

My biggest beef is the failure potential. Plugging, a dent in the pipe means a hot spot, heat loss, solid pack doesn't have these problems.

 

[webbie]

Each chimney type is of different design....it's not as simple as air cooled vs. solid pack. Certainly a solid pack is preferable (in the case of which we are speaking) to an air-cooled which is two walls and has air dumping down the outer wall and into the fireplace compartment (like most pre-fab fireplaces.)

BUT, look closely at the design of some other insulated chimneys....which often use a "dead" air space and/or an air space AND a blanket wrapped around the inner pipe....these are NOT the same as a cheapo two wall pre-fab chimney.

So, perhaps the real question is whether a class A chimney is better than most specific 100% air-cooled chimneys (which are usually only listed for the manufacturers fireplaces or another that has been tested with it). My general opinion would then be YES - class A (and not described always as "solid pack" would be better.

Maybe metal or someone can correct me if I am wrong, but I don't think most generic class A pipe uses circulating air to cool them....in other words, they are not fully open at the bottom and the top?

 

[stoveguy13]

If you are trying to limit you fire place choices i guess this cloud be a way of doing it but it is kind of putting a horse infront of the cart an air cooled chimney will do you just fine in most cases with the fireplaces you may be looking at if we were talking about the a freestanding stove with an outside chimney there would be a whole lot more to disscuss in regards to the function of the chimney but in this case the chimney should be chased and insulated or run inside the house so not such a big factor

 

[jtp10181]

Just in case it went unnoticed. The Quad 7100 IS approved for use with Simpson Durvent "DuraPlus" which is a triple wall vent, one layer is insulation packed. It is only mentioned in two places in the manual but its in there.

http://www.duravent.com/?page=1b.php

 

[Metal]

Web is correct, the air gap in double wall pipe is intended to stop/slow conduction, not to provide convective cooling.